Latent heat storage apparatus

ABSTRACT

A latent heat storage apparatus for obtaining sure latent heat from a latent heat storage material includes a plurality of small chambers for encasing at least the latent heat storage material. A capillary member is provided between the plurality of small chambers so that the contents of the plurality of chambers are coupled to each other. With this arrangement, the crystallization of the latent heat storage material in at least one small chamber is spread out into the other small chambers. In the case that the present invention is applied for a supercooling-prevention type heat storage apparatus, a supercooling-prevention material is encased in one of the small chambers. On the other hand, in the case that the present invention is applied for a supercooling type heat storage apparatus, one end portion of the capillary member is put out so that the latent heat storage material in the small chambers is crystallized by stimulation of the end portion thereof.

This is a division of application Ser. No. 062,650, filed on June 16,1987 now U.S. Pat. No. 4,817,704 granted on April 4, 1989.

BACKGROUND OF THE INVENTION

The present invention relates generally to a supercooling-preventiontype of supercooling type heat storage apparatus having a latent heatstorage material for use in warming systems, heat retaining systems,heating systems and so on.

Latent heat storage materials are being used in hot-water supply andheating application because they have advantages of accumulating greatamount of heat per unit of weight and constant heat output. In practicaluse, the heat storage material is divided into a number of portionswhich are in turn encased in a number of small bags. This is forpreventing deviation of the heat storage material, for making constantthe thickness of the apparatus to improve heating (heat storage)efficiency and, for use in a warming system, to provide flexibility forhuman wear. One example of conventional heat storage apparatus used in aheating system will hereinbelow be described with reference to FIGS. 1and 2. In FIG. 1 and 2, a heat storage apparatus 1 has a number of smallchambers 2 communicated with each other and a heating wire 3 providedfor the small chambers 2 such that the lengths of the heating wire 3 forthe respective smaller chambers 2 are equal to each other. The heatstorage is effected by dissolution of the heat storage materialresulting from energization of the heating wire 3. For use as a heatingsystem, the heating wire 3 is covered by a thermal insulating material 6as shown in FIG. 2 and each of the small chambers 2 encases a latentheat storage material 4 and a supercooling-prevention material 5 foravoiding the supercooling of the latent heat storage material 4. In theconventional apparatus, the control of the heat storage to a constanttemperature is made by the energization and deenergization of theheating wire 3 and may be continued after the heat storage in somecases.

One important problem in the conventional arrangement is, however, thatthe temperatures in the small chambers 2 vary, depending on the locatedpositions, that is, variations in temperature occuring among the smallchambers 2 have a wide distribution. Since the supercooling-preventionmaterial 5 does not act when the temperature exceeds its heat resistingtemperature, it is required that the heating wire 3 is controlled sothat the heating temperature is above the melting point θ1 of the latentheat storage material 4 and below the heat resisting temperature θ2 ofthe supercooling-prevention material 5. This temperature range (θ2-θ1)is not wide. For example, of sodium acetate trihydrate is used as thelatent heat storage material 4 and sodium pyrophosphate decahydrate isused as the supercooling-prevention material 5, the melting point θ1 is58° C. and the heat resisting temperature θ2 is 80° C., that is, therange is about 20° C. Therefore, with the temperature variation of theheat storage apparatus widely occurring some temperatures exceed therange. To avoid going outside the range, it would be required that theheating wire 3 is controlled so that the temperature is graduallyincreased, resulting in a long time being taken for the heat storage.Furthermore, the temperature of the latent heat storage material 4 inthe small chambers 2 covered by a thermal insulating member increasesduring the heat storage. In the case that a thermostat is used fordetection of the temperature, when the small chambers 2 covered by theheat insulating member are in the vicinity of the thermostat, thetemperature can be detected thereby. However, the temperatures of thesmall chambers 2 apart therefrom are difficult to detect and thus thetemperatures of the farther small chambers 2 further increases. Toincrease the number of the thermostats is not desirable in practice.Although it is possible to use a temperature detecting wire as thetemperature detecting device, the temperature detecting wire isdifficult to partially detect the variations of temperatures. Thus, thetemperature of some of the latent heat storage material 4 increases andexceeds the heat resisting temperature θ2 of the supercooling-preventionmaterial 5. During the discharge of heat of the latent heat storagematerial 4, even if the temperature becomes below the melting point θ1,the supercooling phenomenon in which the latent heat is not dischargedoccurs.

The above description has been made in terms of an apparatus having heatstorage material for allowing the prevention of supercooling wherein theheat storage material discharges heat in response to the termination ofthe heat storage and it is impossible to discharge the heat whenrequired. Therefore, attempts to allow the discharge of heat whenrequired have been made hitherto and one example of such techniques isdisclosed in Japanese Patent Provisional Publication No. 61-14283wherein a supercooling type heat storage material is used. However,although the supercooling type heat storage material is liquid duringthe heat storage or supercooling, it is turned into a solid after heatdischarge, resulting in loss of flexibility. The technique to resolvethis problem is disclosed in Japanese Utility Model ProvisionalPublication No. 57-87276 or 57-85154 wherein a plurality of smallchambers is defined by a flexible sheet and a heat storage material isencased in the small chambers so that flexibility is provided by theturns of the coupling portions of the small chambers. However, thesupercooling heat storage material requires a means for collapsing thesupercooling to discharge heat as disclosed in Japanese PatentProvisional Publication No. 61-14283, 61-22194 or 60-1020. The JapanesePatent Provisional Publication No. 61-14283 discloses asupercooling-allowable heat storage component comprisinghydroxylpropylated gua-gum. The heat storage component is supercooled ina glass bottle and, when heat is required a seed crystal is put thereinor the heat storage component is stimulated by a metallic bar so as tocollapse the supercooling to derive heat. The end of the metallic bar issharp and therefore there is a safety problem. Furthermore, the heatstorage component is apt to be leaked during the opening and closing ofthe vessel. The Japanese Patent Provisional Publication No. 61-22194discloses a thermal energy storage device comprising an energy storagemember and a stimulating member. The stimulating member comprising aseed crystal is brought into contact with the energy storage memberwhich is in a supercooling state so that the supercooling is collapsedto derive heat energy. However, this device requires a means forproviding the thermal insulation to aviod the melting of the seedcrystal. The provision of the means makes the device large. Furthermore,the Japanese Patent Provisional Publication discloses a method wherein abendable active strip encased in a receptacle is bent to collapse thesupercooling state. However, a bending stress is frequently applied tothe strip in response to the movement of the device, resulting incollapse of the supercooling when not required. In addition, it isactually difficult to provide such a stimulation means in each of thesmall chambers as disclosed in the Japanese Utility Model ProvisionalPublication Nos. 57-85154 and 57-87276.

SUMMARY OF THE INVENTION

The present invention has been developed in order to remove theabove-mentioned drawbacks inherent to the conventional heat storageapparatus.

It is therefore an object of the present invention to provide a new andimproved latent heat storage apparatus which is capable of providingflexibility and surely utilize the latent heat.

A feature of the present invention is that a plurality of small chambersis defined by partial connection between the upper portions and thelower portions of a receptacle and at least one heat storage material isencased in the plurality of the small chambers. This arrangementprovides flexibility to the heat storage apparatus because the turns ofthe connected portions are allowable.

Another feature of the present invention is that the plurality of smallchambers is arranged so as to communicate with each other throughcommunicating passages so that the contents (heat storage material) inthe plurality of small chambers are coupled to each other. Thisarrangement results in the fact that as long as at least one smallchamber is not in the supercooling state even if most of the smallchambers are in the supercooling state, the entire heat storage devicedoes not enter into the supercooling state, resulting in shortening theheat storage time period and in obtaining heat from the heat storagedevice. That is, when the latent heat storage material in one smallchamber is changed from a liquid to a solid (crystallization), thischange is communicated with the adjacent small chambers through thecommunicating passages. Even if the latent heat storage material in theadjacent small chambers is in the supercooling state, the communicationresults in insertion of a seed crystal to collapse the supercoolingstate to discharge heat. This change successively communicates with theother small chambers and the heat storage device thus entirelydischarges its heat.

In accordance with the present invention, there is provided a heatstorage apparatus comprising a plurality of chambers for encasing atleast a latent heat storage material and coupling means provided betweenthe plurality of chambers so that the plurality of chambers is coupledto each other, a supercooling-prevention material being encased in atleast one of the chambers.

In accordance with the present invention, there is also provided a heatstorage apparatus comprising a receptable having therein a heat storagematerial for allowing supercooling and discharging latent heat by thephase change from liquid to solid in response to stimulation and acapillary member which extends from the inside of said receptacle to theoutside thereof.

In accordance with the present invention, there is further provided asupercooling type heat storage apparatus comprising a plurality ofchambers each having therein a heat storage material for allowingsupercooling and discharging latent heat by the phase change from liquidto solid in response to stimulation and a capillary member provided topass through said chambers.

Preferably, the communicating means is constructed of a capillary tube.In this case, even if all of the heat storage material in the pluralityof chambers is in the supercooling state, it is possible to dischargethe latent heat by stimulation of the capillary tube. Furthermore, evenif an external force is applied to the heat storage apparatus, thelatent heat storage material is difficult to leak to the outside.

When the heat storage device comprising the plurality of the smallchambers and heat storage material encased therein is heated by aheater, the difference in temperature arises between the center portionsand peripheral portions of the heat storage device. If the heat storagedevice is heated by the heater to store heat as quickly as possible withthe temperature of one of the peripheral small chambers being set to bebelow the heat resisting temperature of a supercooling-preventionmaterial, the temperature of the small chambers at the center portionbecomes above the heat resisting temperature of thesupercooling-prevention material and the supercooling state occurs inresponse to the heat discharge after the termination of the heating.According to the present invention, the small chambers at the peripheralportions do not enter into the supercooling state and thecrystallization occurs in the vicinity of the melting point of thelatent heat storage material. This crystallization is transferred to thesmall chambers at the center portion and hence the latent heat storagematerial does not become supercooled. This is achieved with asupercooling prevention material being encased in one of the smallchambers at the peripheral portion. Furthermore, even in the case thatsome of the small chambers are covered by a heat insulating member, thecrystallization in the small chambers which are not covered by the heatinsulating material is transferred to the small chambers which arecovered thereby. As result, even if the temperature in the covered smallchambers exceeds the heat resisting temperature of thesupercooling-prevention material due to the covering, the latent heatcan be obtaiend from the covered small chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

The object and features of the present invention will become morereadily apparent from the following detailed description of thepreferred embodiments taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a perspective view of a conventional heat storage apparatus;

FIG. 2 is a perspective view of a heating apparatus including theconventional heat storage apparatus of FIG. 1;

FIG. 3 is a perspective view of a heat storage apparatus according tofirst and second embodiments of the present invention;

FIG. 4 is a cross-sectional view of the heat storage apparatus of FIG.3;

FIG. 5 is a plan view of a heat storage apparatus according to a thirdembodiment of the present invention;

FIG. 6 is a cross-sectional view of the heat storage apparatus of FIG.5;

FIG. 7 is a cross-sectional view of a heating apparatus including theheat storage apparatus of FIG. 5;

FIG. 8 is a cross-sectional view of a heat storage apparatus accordingto a fourth embodiment of the present invention;

FIG. 9 is a cross-sectional view of a heat storage apparatus accordingto a fifth embodiment of the present invention;

FIG. 10 is a cross-sectional view of a heat storage apparatus accordingto a sixth embodiment of the present invention;

FIG. 11 is a cross-sectional view of a heat storage apparatus accordingto a seventh embodiment of the present invention;

FIG. 12 is a plan view of a heat storage apparatus according to a eighthembodiment of the present invention; and

FIG. 13 is a cross-sectional view of the heat storage apparatus of FIG.12.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

A first embodiment of the present invention will hereinbelow bedescribed with reference to FIGS. 3 and 4, FIG. 3 being a perspectiveview of a heat storage apparatus according to the first embodiment ofthe invention and FIG. 4 being a cross-sectional view of the heatstorage apparatus incorporated into a heating apparatus. In FIGS. 3 and4, the heat storage apparatus 1 comprises a plurality of small chambers2 which are defined by division of the inner space of a flat receptacle7 of a fusible film. The division is made by partial attachment of theupper surface and the lower surface of the flat receptacle. Thereference numeral 8 represents adhesion portions. A latent heat storagematerial 4 and a supercooling-prevention material 5 are encased in eachof the plurality of small chambers 2. Also included in the heat storageapparatus 1 is a communicating device 9 provided to pass through theplurality of small chambers 2 so that the contents (heat storagematerial 4) in the plurality of small chambers 2 are coupled to eachother through the communicating device 9. In this embodiment, thecommunicating device 9 comprises a member such as yarn for allowing thecapillary phenomenon. The heat storage material 4 in one small chamber 2soaks into the communicating device 9 and is coupled to the heat storagematerial 4 in the adjacent small chamber 2. It is also appropriate thatcapillary tubes are used as the communicating device 9. In this case,each of the capillary tubes is provided between the small chambers 2.

The receptacle 7 is made of a flexible material such asaluminum-laminating film which is not reactive and compatible to thelatent heat storage material 4. The receptable 7 may be made by heatingattachment of a pair of film sheets, by heating attachment of a foldedfilm sheet, or by heating attachment of the suitable portions of a tube.A description will hereinbelow be made in terms of the receptacle madeof a pair of film sheets. The adhesion of the upper surface and lowersurface of the receptacle 7 is made by heating. It is also appropriatethat the adhesion is made using an adhesive bond. The small chambers canbe determined in size and shape in accordance with the use purposes. Thelatent heat storage material 4 is of the hydrated salt suuch as calciumchloride hexahydrate, sodium sulfate decahydrate, sodium thiosulfatepentahydrate, or sodium acetate trihydrate. Because the latent heatstorage material 4 enters into the supercooling state by heating overthe melting point and cooling, a supercooling-prevention material ismixed therein. In addition, a viscosity increasing agent, a stabilizeror a heat-conduction material is mixed therein if required. Thecapillary member 9 is a fiber-made member which is not reactive and notcompatible to the latent heat storage material 4. For example, thecapillary member 9 is a yarn-like member made of a natural fiber such ascotton and cellulose or a synthetic fiber such as polyester, acrylic,polyamide and aromatic polyamide. It is also appropriate that thecapillary member 9 is a woven fabric, non-woven fabric, a member made offine metallic lines such as stainless steel line and copper line, or oneof various types of continuous bubble members. The heating attachment isperformed with the capillary member 9 being interposed between the twofilm sheets so that the capillary member 9 is fixed after the heatingattachment. It is necessary that capillary member 9 with stand the heatfor the heating attachment. If the capillary member 9 is melted into thereceptacle 7, it does not function as the capillary and the latent heatstorage material 4 liquid becomes difficult to permeate thereinto sothat the collapse of the supercooling is terminated there. Therefore, itis preferable to use a yarn like member made of polyester or polyamidewhen the most-inner layer (heating attachment layer) of the laminatingfilm is polyethylene, for example. The installing position andinstalling method of the capillary member 9 are not limited particularlyand it is enough if it is arranged to perform the connection between thesmall chambers 2 through coupling portions 8.

As shown in FIG. 3, a yarn made of polyester as the capillary member 9is interposed between two sheets of laminating films and the heatingattachment thereof is effected to have bonding portions of a width of 5mm so that a plurality of small chambers of 4×6 cm is defined. Beforethe heating attachment, the capillary member 9 is arranged so that thesmall chambers 2 are coupled to each other in at least one place. Sodiumacetate trihydrate is encased as the latent heat storage material 4 inthe small chambers 2. In addition, sodium pyrophosphate decahydrate,i.e., supercooling prevention material 5 is further encased in only thesmall chamber 2a. Thereafter, the openings of the small chambers 2 areclosed under condition of decreased pressure. Thus, a heat storagedevice is constructed to have 30 small chambers 2, that is, 10 chambersper row and three rows. A heater as shown in FIG. 1 is provided to theheat storage device. A temperature control device is placed on the smallchamber 2a, and with the temperature control being performed so that thetemperature of the small chamber 2a exceeds 75° C., the energization ofthe heater (heat storage) is effected. In the temperature distributionof the heat storage device after the heat storage termination of thesmall chamber 2a, the temperature of the small chambers 2 at the cornerportions is about 75° C., the temperature of the small chambers 2 at theperipheral portions other than the small chambers at the corner portionsis 85° to 95° C., and the temperature of the small chambers 2 at thecenter portion is 90° to 100° C. If the small chambers 2 are completelyindependent of each other, these temperatures provide the supercoolingfor all of the small chambers 2 other than the small chamber 2a.Furthermore, the time period is half the time period taken in theconventional temperature-controlling type apparatus. The heat dischargeis started immediately after the heat storage. The small chambers 2 atthe corner portions have the greatest degree in the decreasingtemperature and the small chambers 2 at the peripheral portion aresecond to the small chambers 2 at the corner portions. When thetemperature is in the vicinity of the melting point of the latent heatstorage material 4 in accordance with the temperature decrease, thephase change from liquid to solid occurs in the small chamber 2a,resulting in discharging heat. Secondly, when the temperature of thesmall chamber 2 adjacent to the small chamber 2a becomes below themelting point of the latent heat storage material 4, the phase changeoccurs in the adjacent small chamber 2. This phase change istransferred, or spread out, one after the other and the latent heat ofthe entire heat storage device could be obtained. Furthermore, duringthe heating, a force of 150 kg is applied to one of the small chambers2. However, the heat storage material 4 in the force-applied smallchamber 2 has not been transferred to the other chambers 2, because themovement of the latent heat storage material 4 is significantly limitedby the receptacle 7.

Embodiment 2

As well as in the first embodiment, a heat storage device is constructedso as to have 30 small chambers, that is, 10 chambers per row and threerows. In this embodiment, sodium acetate trihydrate and sodiumpyrophosphate decahydrate are encased in each of the small chambers andthey are mixed with each other. In the case that the heat storage deviceis partially covered by a heat-insulating member during heat storage andthe abnormality that the heat storage member is covered by theheat-insulating member is not detected sufficiently and the control isnot effected, the temperature of the covered portion is greater andexceeds the heat-resisting temperature 80° C. of thesupercooling-prevention material. If the small chambers are independentof each other, the supercooling occurs and thus it is impossible toobtain heat from the small chambers 2 at the covered portion. Therefore,according to this embodiment, because the contents (latent heat storagematerial 4) in the small chambers are coupled to each other through thecapillary member 9, when the phase change from liquid to solid occursduring heat discharge in terms of the latent heat storage material 4 ofthe small chambers 2 which is not covered, the covered small chambers 2adjacent thereto result in the phase change from liquid to solid throughthe capillary member 9, and this allows the latent heat of the latentheat storage material 4 to be obtained without the generation ofsupercooling. Although the above-description has been made in the caseof the provision of the heater, it is also appropriate that the heatingwire is not provided at a portion of the small chamber and thetemperature control is effected at the portion. Furthermore, a similareffect can be obtained using heat wind or hot water in place of theheater. When the heat storage device is mounted on a human body, it iseasily bent around the attachment portions and therefore the human doesnot feel incompatibility, resulting in good heating.

Embodiment 3

As shown in FIGS. 5 and 6, a heat storage apparatus 1 has a capillarymember 9 which is coupled from the inside to the outside. Sodium acetatetrihydrate is used as a latent heat storage material 4 and polyesteryarn is used as the capillary member 9. Because the length of thecapillary member 9 is long, the capillary member 9 contains the sodiumacetate in advance. The capillary member 9 is covered by a shell 10. Ifit is used several times, the shell 10 is not required. However, forincreasing the number of uses, the shell 10 made of the same material asthe receptacle is provided over the whole of the capillary member 9 notto result in composition change due to evaporation of water content. Thereceptacle and the shell 10 are bonded so that the entire heat storageapparatus 1 is in the sealed state. A wire 3 is provided thereto forheat storage and the circumference thereof is covered by athermal-insulating material 6 so that a heating apparatus 11 as shown inFIG. 7 can be constructed. One end of the capillary member 9 is placedto the outside of the thermal-insulating material 6. When the heatingapparatus 11 is heated by the wire 3, the temperature of the sodiumacetate trihydrate has reached 90° C. and the heat storage has beeneffected. At this time, the temperature of the one end of the capillarymember 9 placed outside the thermal-insulating material 6 is 35° C.which is lower than the melting point 58° C. of the sodium acetatetrihydrate. When heat is discharged, the crystal remaining in thecapillary member 9 is used as a seed crystal and heat can be obtainedfrom the heat storage apparatus 1 in accordance with the progression ofcrystallization.

Embodiment 4

Although in the first and second embodiments the small chambers arecoupled to each other through the capillary member 9, in thisembodiment, the capillary member 9 is not used and adhesion portions 8for defining the small chambers are not completely adhered as shown inFIG. 8 so that the contents in the small chambers 2 are coupled to eachother through the non-adhered portions 12. There is a close relationshipbetween the dimension of the non-adhered portion 12 and the movement ofthe latent heat storage material 4 and it is preferable that the widthof the non-adhered portion 12 is half the length thereof. When the widththereof is greater than half the length thereof, in response toapplication of a force to one small chamber 2 the latent heat storagematerial 4 in the force-applied small chamber 2 is easily moved to othersmall chambers 2, resulting in deviation of the amount of the latentheat storage material 4 in the small chambers 2. Furthermore, it ispreferable that the width of the non-adhered portion 12 is below 10 mmbecause of the prevention of easy movement. With the above-mentionedarrangement, the heat storage device is heated by a heater as in thefirst embodiment. As a result, the crystallization occurs from the smallchamber 2a, which is not in the supercooling state, to other smallchambers 2 whereby latent heat can be obtained from the entire heatstorage device.

Second, a description will hereinbelow be made in the case that thepresent invention is applied to a supercooling type heat storageapparatus. A latent heat storage material which discharges heat by thephase change effected in response to a stimulation is encased in one ora plurality of small chambers and the small chamber is provided with acapillary member which extends from the inside of the small chamber tothe outside thereof. The supercooling of the latent heat storagematerial is collapsed by the stimulation of the capillary member. Thestimulation of the capillary member results in the stimulation of thelatent heat storage material.

Embodiment 5

A heat storage apparatus of this embodiment is shown in FIG. 9 ascomprising a receptacle 13, a latent heat storage material 4 encasedtherein, and a capillary member 9 provided thereto. If required, thecapillary member is covered by a cover 14.

The receptacle 13 is made of a material which is not reactive and notcompatible with the latent heat storage material 4. If the heat storageapparatus is employed for a warming apparatus, an aluminium-laminatingfilm may be used for providing flexibility. The latent heat storagematerial 4 is of the hydrated salt such as calcium chloride hexahydrate,sodium sulfate decahydrate, sodium thiosulfate pentahydrate, or sodiumacetate trihydrate. In addition, a viscosity increasing agent, astabilizer or a heat-conduction material is mixed therein if required.The capillary member 9 is a fiber-made member which is not reactive andnot compatible to the latent heat storage material 4. For example, thecapillary member 9 is a yarn-like member made of a natural fiber such ascotton and cellulose or a synthetic fiber such as polyester, acrylic,polyamide and aromatic polyamide. It is also appropriate that thecapillary member 9 is a woven fabric, non-woven fabric, a member made offine metallic lines such as stainless steel line and copper line, acontinuous bubble member such as polyurethane, elastomer havingcontinuous bubbles and metallic bubble body, or sinter having continuousbubbles such as polyethylene porous sinter and porous ceramic. Thecapillary member 9 is arranged such that one end thereof is outside thereceptacle 13 and the other end thereof is brought into contact with theheat storage material 4 therein. The capillary member 9 draws up thelatent heat storage material 4 by the contact therewith and is entirelysoaked therein. In the case that the internal pressure of the receptacle13 is increased by increase of the temperature during heat storage, thelatent heat storage material 4 may be leaked out through the capillarymember 9. Thus, it is required that the capillary member 9 is designedconsidering the kind of the latent heat storage material 4 and viscositydecrease due to temperature increase so that the leaking of the latentheat storage material 4 is substantially prevented.

The heat storage apparatus 1 is heated (heat-stored) by hot water or aheater. When the latent heat storage material 4 is cooled to the roomtemperature after being sufficiently melted, the latent heat storagematerial 4 becomes in the supercooling state. Here, the supercoolingstate is collapsed even if the heat storage apparatus 1 is shocked, bentor pressurized. For obtaining heat, a portion of the capillary member 9provided outside the receptacle 13 is stimulated. That is, the surfaceof the capillary member 9, particularly the portion close to thereceptacle 13, is stimulated by a bar-like member, thin member or afinger. If a seed crystal for the latent heat storage material 4 isattached to the stimulating member, the collapse of the supercooling iseasily effected by light contact therewith. If the collapse of thesupercooling is started at once, it is successively performed. That is,the collapse of the supercooling started at the stimulated portion isspread out, through the capillary member 9, all over the latent heatstorage material 4 in the receptacle 13, resulting in obtaining heatfrom the latent heat storage material 4.

the cover 14 protects the capillary member 9 protruding from thereceptacle 13 and prevents evaporation of water from the capillarymember 9. This prevents the collapse of the supercooling which may beeffected by an undersirable stimulation performed when the heat storageapparatus 1 is held or carried in the supercooling state. Furthermore,when the temperature of the heat storage apparatus 1 is increased duringheat storage, the crystallization water of the latent heat storagematerial 4 is apt to be evaporated. The covering of the capillary member9 results in prevention of the evaporation.

A detailed arrangement of the heat storage apparatus 1 will be madehereinbelow. Two aluminum-laminating films are prepared, and with thembeing piled up, the three sides thereof are heated to form a receptacle.A polyester yarn of 0.2 mm diameter used as the capillary member isinterposed between the two aluminum-laminating films at the remainingside. The dimension of the receptacle is 100 mm×120 mm, and the width ofthe heated portion is 5 mm. The length of the polyester yarn protrudedfrom the receptacle is 20 mm and the length inside the receptacle is 50mm. A cover for covering the capillary member is provided at the side inwhich the capillary member is placed. The cover is made of analuminium-laminating film and the length thereof is 20 mm. For makingthe heat storage apparatus, a latent heat storage material of 40 g isencased in the receptacle. The capillary member protruded from thereceptacle is put in the cover so that the whole thereof is coveredthereby, followed by heating (heat storage). When the latent heatstorage material is cooled to the room temperature after beingsufficiently melted, the latent heat storage material enter into thesupercooling state. The supercooling has not been collapsed by anyexternal stimulations. The capillary member is stimulated by astimulating bar with a seed crystal. As a result, the supercooling statecollapses and heat could be obtained. The collapse by the stimulation istransferred through the polyester yarn to the heat storage material.Although the internal pressure is increased during the heating, the heatstorage material has not been leaked out.

Embodiment 6

A heat storage apparatus of this embodiment will be described withreference to FIG. 10. The heat storage apparatus 1 has a port 15 intowhich a capillary member is inserted and an opening and closing device16 as shown in FIG. 10. A latent heat storage material 4 is encased in areceptacle 13.

The arrangement of the heat storage apparatus 1 will hereinbelow bedescribed in detail. A polyethylene-made pipe having a polyethylenesinter therein as the capillary member 9 having a dimension of 100mm×120 mm and made of an aluminum-laminating film is adhered by heatingto the receptacle 13. The opening and closing device 16 comprises apolyethylene-made cap for covering the polyethylene pipe to seal thereceptacle 13. Sodium acetate trihydrate of 40 g is encased in thereceptacle 13 and sealed up under the condition of decreased pressure sothat the heat storage apparatus 1 can be constructed. The heat storageapparatus is soaked in hot water of 100° C. so that the latent heatstorage material 4 is sufficiently melted, and it is cooled to the roomtemperature, and hence the latent heat storage material becomes in thesupercooling state. The supercooling has not been collapsed by any ofthe stimulations. For obtaining heat, the cap 16 is removed from thereceptacle 13 and the surface of the polyethylene sinter is stimulatedlightly by a bar. The supercooling of the latent heat storage material 4is easily collapsed by the stimulation. In this embodiment, when theheat storage apparatus 1 is not used, since it is covered by the cap 16,the supercooling state is not collapsed by an undesirable stimulation.Furthermore, the heat storage apparatus 1 is sealed up when heat-storedor kept, and therefore, the change of composition of the heat storagematerial due to evaporation of water does not occur. Even if the cap isremoved, the latent heat storage material 4 is not leaked out because ofinterruption of the capillary member 9.

Embodiment 7

A heat storage apparatus 1 according to this embodiment will hereinbelowbe described with reference to FIG. 11. The heat storage apparatus 1comprises a receptacle 13 having a latent heat storage material 4therein and a capillary member 9 which extends from the inside of thereceptacle 13 to the outside thereof. The capillary member 9 isseparated into two portions 9a and 9b and a switching device 17 isprovided therebetween so that the two portions 9a and 9b are switchedinto and out of contact with each other. The one end of the capillarymember 9a is inserted into the receptacle 13 so that it is in contactwith the latent heat storage material 4. Thus, the latent heat storagematerial 4 is soaked into the capillary member 9a, that is, thecapillary member 9a carries the latent heat storage material 4. Thelatent heat storage material 4 is previously soaked into the capillarymember 9b. The latent heat storage material 4 in the capillary member 9bis held by capillary phenomenon. While the latent heat storage material4 in the capillary member 9a is melted during heat storage, thecapillary member 9b is separated from a heater so that a portion of thelatent heat storage material 4 in the capillary member 9 is not melted,i.e., remains in the crystal state. After the heat storage, thenon-melted portion in the capillary member 9b results in a seed crystaland the latent heat storage material 4 in the capillary member 9b isentirely crystallized. On the other hand, the capillary member 9a doesnot contain the seed crystal and enters into the supercooling state.When a knob 18 of the switching device 17 is operated so that thecapillary member 9b is moved into contact with the capillary member 9a,the supercooling state of the latent heat storage material 4 in thecapillary member 9a collapses because the latent heat storage material 4of the capillary member 9b acts as a seed crystal. This collapse istransferred through the capillary member 9a to the latent heat storagematerial 4 in the receptacle 13. As a result, the latent heat storagematerial 4 discharges heat by the phase change from liquid to solid.

Secondly, in the case that the receptacle 13 is divided into a pluralityof small chambers for the purpose of providing flexibility to the heatstorage apparatus 1, a description will be made in terms of a method forcollapsing the supercooling state in each of the small chambers. Alatent heat storage material 4 whose supercooling state is easilycollapsed by stimulation is encased in each of the small chambers. Thesmall chambers are coupled to each other through a capillary member.Cince the capillary member is in contact with the latent heat storagematerial in the small chambers, the latent heat storage material issoaked into the capillary member by capillary phenomenon, that is, thecapillary member includes the latent heat storage material. Thus,although the receptacle is divided into the plurality of small chambers,the contents in the small chambers are connected to each other throughthe capillary member. When a stimulating member provided in one of thesmall chambers is operated, the supercooling state of the latent heatstorage material in the small chamber is collapsed and the latent heatstorage material discharges heat by the phase change from liquid tosolid. After entirely collapsed in a small chamber, the collapse of thesupercooling is transferred through the latent heat storage material viathe capillary member to the latent heat storage material in the adjacentsmall chambers so that the latent heat storage material in all of thesmall chambers is collapsed. That is, the collapse of the supercoolingin one small chamber results in the collapse of the supercooling in allof the small chambers by means of the capillary member.

Embodiment 8

A further embodiment of the present invention will be described withreference to FIGS. 12 and 13. FIG. 12 is a plan view of a heat storageapparatus according to this embodiment and FIG. 13 is a cross-sectionalview of the heat storage apparatus of FIG. 12. The heat storageapparatus 1 has a plurality of small chambers 2 which are defined bypartially adhesion of a receptacle made of films or a tube. A latentheat storage material described in the first embodiment is encased ineach of the small chambers 2 and the small chambers are coupled to eachother through a capillary member 9. A description of the heat storageapparatus 1 will hereinbelow be made in detail.

A yarn made of polyester is, as the capillary member 9, interposedbetween two aluminium-laminating films which are made of polyethylene,and the aluminium-laminating films are partially adhered by heating sothat a plurality of small chambers 2 are defined by the adhesionportions 8. The width of the adhesion portions 8 is 5 mm and thedimension of each of the small chambers is 5×5 cm. The capillary member9 is arranged so that the small chambers 2 are coupled in one place toeach other through the capillary member 9 upon heating. Sodium acetatetrihydrate of 20 g, i.e., latent heat storage material 4, is encased ineach of the small chambers 2 and after encased, the small chambers 2 aresealed up under the condition of decreased pressure, thereby defining 30small chambers, 4 chambers per row and two rows. A stimulating member 19is provided for one of the small chambers 2. The heat storage apparatus1 is heated to 80° C. higher than the melting point 58° C. of the sodiumacetate trihydrate. After the latent heat storage material 4 has beenmelted completely, it is cooled to the room temperature whereby thelatent heat storage material 4 easily enters into the supercoolingstate. The force of 150 Kg has been applied to one of the small chambers2 during the heating. However, the latent heat storage material in thesmall chamber 2 has been transferred to other chambers 2. This isbecause the movement of the latent heat storage material 4 is extremelylimited by the capillary member 9. The supercooling state is collapsedby stimulating the stimulating member 19 whereby heat can be obtainedfrom the whole of the heat storage apparatus 1. Even if the heat storageapparatus is mounted on a human body, there is no feeling ofincompatibility because of rotations about the adhesion portions 8.

Embodiment 9

In this embodiment, as well as in the fourth embodiment, each adhesionportion is not adhered completely so that the contents (latent heatstorage material) in the small chambers are coupled to each otherthrough the non-adhered portions. As shown in FIG. 12, a stimulatingmember is provided for one of the small chambers. In response tostimulation of the latent heat storage material in the small chamber bythe stimulating member, as well as in the eighth embodiment, thesupercooling state is collapsed and heat can be obtained from the heatstorage apparatus.

In the above-description, the embodiments 1, 2, 3 and 4 respectivelyrepresent a supercooling-prevention type heat storage apparatus.According to these apparatus, a latent heat storage material is encasedin a plurality of small chambers and the plurality of small chambers iscoupled to each other, for example, a capillary member so that thecontents in the small chambers are substantially coupled to each other.Therefore, even if one small chamber is not in the supercooling stateand the latent heat storage material in the one small chamber results inthe phase change from liquid to solid, the phase change is transferredto the whole of the heat storage apparatus whereby latent heat can beobtained from the entire apparatus. Therefore, the temperature in theother small chambers is allowed to exceed the heat-resisting temperatureof a supercooling-prevention material and it is possible to set theheating temperature to a temperature higher than the melting point ofthe latent heat storage material, thereby shortening the time period ofheat storage. Furthermore, in the case that the heat storage apparatusis mounted on a human body, the adhesion portions between the smallchambers are turned easily and hence there is no feeling ofincompatibility. In addition, in the case that the small chambers arecoupled to each other through a capillary member, even if a great forceis applied to one of the small chambers, the latent heat storagematerial in the small chamber is not substantially transferred to theother chambers because the movement of the latent heat storage materialis interrupted by the capillary member.

On the other hand, the embodiments 5, 6, 7, 8 and 9 respectivelyrepresent a supercooling type heat storage apparatus. According to thesupercooling type heat storage apparatus, a plurality of small chambersis defined and the plurality of small chambers is coupled to each otherthrough a capillary member, for example. The supercooling state of thelatent heat storage material in one small chamber is collapsed bystimulation. This collapse of the supercooling results in obtaininglatent heat from the whole of the heat storage apparatus because ofspread to the latent heat storage material in the other small chambers.The flexibility of the heat storage apparatus is easily achieved byturns of the adhesion portions between the small chambers.

It should be understood that the foregoing relates to only preferredembodiments of the present invention, and that it is intended to coverall changes and modifications of the embodiments of the invention hereinused for the purposes of the disclosure, which do not constitutedepartures from the spirit and scope of the invention.

What is claimed is:
 1. A heat storage apparatus comprising a receptaclefilled with a heat storage material for allowing supercooling anddischarging latent heat by a phase change from liquid to solid inresponse to stimulation, said receptacle being provided with a port, acapillary member to be stimulated being tightly fitted in said port andhaving a portion thereof embedded in said heat storage material, andsaid port being covered with a removable cap for preventing saidcapillary member from being exposed to the outside air and from beingaccidentally stimulated, wherein, for obtaining heat, said removable capis removed from the receptacle and said capillary member is stimulated.2. A heat storage apparatus as claimed in claim 1, wherein saidcapillary member is a yarn-like member.